CA1110979A

CA1110979A - Device for the separation of liquid from a slurryladen fluid

Info

Publication number: CA1110979A
Application number: CA291,376A
Authority: CA
Inventors: Ingvar Johansson
Original assignee: Individual
Current assignee: Individual
Priority date: 1976-11-22
Filing date: 1977-11-21
Publication date: 1981-10-20
Also published as: SE7613012L; NO773974L; JPS5387063A; FI773455A; DE2751091A1; DK147097C; BR7707729A; AT352651B; NL7712485A; CH620593A5; GB1596414A; DK147097B; JPS6049004B2; DK511477A; SE402716B; FI63525B; DE2751091C2; ATA826177A; NO143255B; FI63525C

Abstract

ABSTRACT OF THE DISCLOSURE
A device for the separation of liquid from a slurry comprising a rotatable drum having a perforated wall and an internal helical flange fixed to and extending inwards from the drum wall to feed slurry along the drum from an in-take end to a discharge end, wherein the axis of rotation of the drum is inclined upwards from the intake end towards the discharge end on the flange decreases in height from the intake end towards the discharge end over at least a part of the length of the drum and the drum has a central spillway opening at the intake end for the overflow of excess slurry.

Description

g~9 ~ e l~:L(~ nt invcn,-ion r~ s -to a de-~ice ror the sep~lr-ltioll of liqui.d :~rom a slu~ry.
It is a principal object of the invention to provide a water ~;epara-tor of the kind mentioned by means of which it is prevented that surplus ]i~uid is entrained with the nor-mally dewatered residues fed out throuyh the discharge end of -the drum, when the quantity of slurry supplied exceeds t'r.e capacity of the device.
According to the present invention, ~here is provided a device ~or the separation of liquid from a slurry compr;sing a rotatable drum having a perforated wall and an internal heli-cal fl.ange fixed to and extending inwards from the drum wall to feed slurry along the drum from an intake end to a dis-charge end, wherein the axis of rotation of the drum is incli-ned upwards from the intake end towards the discharge end and the flanqe decreases in height from the intake end towards the discharge end over at least a part of the length of the drum and the drum has a central spillway opening at the intake end for the overflow of excess slurry.
An example of embodiment of the invention will be described in the following, reference being made to the accom-panying drawings, in which:
figure 1 is a schematic view of a longitudinal cross-section through a dewatering device made according to the invention; and figure 2 is a schematical view of the same device as seen from the left in figure 1.
The dewatering device illustrated in the drawings includes a dewatering drum in its entirety indicated with 1 and comprising a perforated cylindrical mantle wall 2, at the rear being partly closed by means of an end wall 3. At its opposite end an end wall 4 of the shape o:~ the frustrum of a cone connects to the mantle wall, which end wall 4 in its turn defines a dis~

charge opening in the narrow portion of the cone. A pipe socket 5 facing backwards as counted in the direction of feed connects to the end wall 3 and is coaxially arranged relative to the mantle of the dewatering drum. In slightly concentrical arrangement, i.e.
somewhat displaced in upwards direction a feeding tube 6 extends into the interior of the dewatering drum, said tube 6 in the il-lustrated example of embodiment exhibiting a slightly chamfered end 6a. In addition, the inlet tube at its end portion is provided with an outlet opening 6b, which is indicated with a broken line and which in the illustrated example exhibits a triangular shape.
The slurry supplied flows out of this opening in the direction of the arrow indicated with 7, i.e. in sidewise direction to the mantle wall of the drum 2. The dewatering drum is supported by a number of supporting rollers 8 and 9 respectively, preferably in pairwise arrangement at each one of the ends of the drum. These rollers can preferably also be vertically adjustable in order to make possible an adjustable setting of the angle of inclination of the mantle of the drum. A feeding device 10 intended for the feed of the slurry, which shall be dewatered, is mounted inside the drum, said feeding device having the shape of a screw flange, which ex-tends in radial direction from the inside of the mantle 2 towards the centre of the dru~. As is evident from figure 1, the screw 10 exhibits a diminishing height of the flange as counted in the direction of feed. In the embodiment illustrated the height of the flange is greatest at a, while the height of the flange of its portion b is somewhat smaller, the height of the flange at the por-tion c being the smallest one. The screw terminates with a por-tion d, which in the illustrated embodiment exhibits about the same height of the flange as the portion a. Instead of a step-wise diminishing of the height of the flange as in the embodimentillustrated it is of course within the scope of the fundamental idea of the invention to let the height of the flange diminish by ;g79 tapering off in the direction from the input end to the screw por-tion d. As is also evident from the figure 1, the screw portions b and c also exhibit a smaller pitch than the portions having a full height of the flange, which leads to a better filling degree and a better utilization of the whole surface of the mantle of the drum in spite of the oblique angle of the inclination of the setting.
Liquid is normally separated from the slurry through the mantle of the drum and flows down in the direction of the arrow 11 into a collecting vat 12 provided below the dewatering drum, and from there it is fed out via a discharge pipe 13. The end wall 3 of the in-take side supports a driving gear ring 14 extending peripherically and engaging a driving gear 15, which is connected to the outgoing shaft gear of a driving motor 16. The driving motor drives the dewatering drum in colmter-clodkwise direction according to figure

2, as is hinted by the arrow 17. Further, a brush 19 rotating in the direction of the arrow 18 and provided with comparatively stiff bristles is pressing against the mantle of the drum The brush 19 can possibly be driven by the mantle by lying against the same, so that its bristles penetrate into the perforations of the mantle of the drum and efficiently get cleansed from impurities. However, if in spite of this the perforations of the drum would be clogged, there-by causing an increase of the volume of fluid inside the drum, the surplus fluid will flow out in the direction of the arrow 20 in figure 1 over the spillway drain shaped by the pipe socket 5 being at a lower level than the bottom edge of the discharge opening of the drum at the opposite side. The surplus fluid flows down into a collecting vat 21, and from there it is conveyed further on via a drainage pipe 22. This fluid can by way of example be returned to the dewatering device via the intake pipe 6. Because of the diminishing height of the feed screw, an efficient separation of surplus fluid is taking place along practically the whole length of the feed screw. Thus, there is no risk that non-dewatered mate 7~

rial is fed out of the drum and via the discharge chute 23 being conveyed to the point, where dewatered material is collected. More-over, the arrangement illustrated under normal working conditions, i.e. without any surplus liquid being introduced into the device, has a very good dewatering effect, and the material leaving the device is very dry.
The invention is not limited by the example of embodi-ment described above and illustrated in the drawings. By way of example a sensing element can also be provided in connection with the spillway drain, which sensing device gives a regulation of the quantity of slurry introduced into the device.

Claims

The embodiments of the invention in which an exclu-sive property or privilege is claimed, are defined as follows:

1. A device for the separation of liquid from a slurry comprising a rotatable drum having a perforated wall and an internal helical flange fixed to and extending inwards From the drum wall to feed slurry along the drum from an intake end to a discharge end, wherein the axis of rotation of the drum is inclined upwards from the intake end towards the discharge end and the flange decreases in height from the intake end towards the discharge end over at least a part of the length of the drum and the drum has a central spillway opening at the intake end for the overflow of excess slurry.

2. A device as claimed in claim 1 in which the flange has a portion at the discharge end which is of increased height relative to the preceding portion.

3. A device as claimed in claim 2, in which the decrease in height of the flange is continuous over the said part of the length of the drum.

4. A device as claimed in claim 1, in which the decrease in height of the flange is accompanied by a decrease in pitch.

5. A device as claimed in claim 1, 3 or 4, in which the discharge end of the drum has an end wall of frusto-conical form tapering towards a discharge opening.

6. A device as claimed in claim 1, 3 or 4, in which the spillway opening is formed by a pipe coaxial with the drum and extending outwards form the intake end wall of the drum.

7. A device as claimed in claim 1, 3 or 4 having a sensing device associated with the spillway opening to sense the outflow of slurry through the spillway opening, the sen-sing device being connected to regulate the supply of slurry.